In a principal aspect, the present invention relates to a method for machining a surface and, more particularly to a method for matching an edge surface on a composite panel material.
Panels made of composite, multiple layered materials have many applications. Such panels may have a particleboard interior and decorative plastic outer surface layers. They may be used in the fabrication or manufacture of furniture, wall dividers and the like.
The manufacture of panels of this type requires many sequential cutting and shaping operations. For example, preparation of two panels to form a right angle requires cutting, preshaping, final shaping, grooving and sizing the edges of each panel. In the past, these operations have required at least four separate steps by various items of equipment. Thus, the panel is initially sized by operation of a saw or similar cutting device to within 1/2 inch of final dimension. Next, the edge of the panel is "hogged" and/or premitered to provide a generally acceptable panel edge. Subsequently, the panel is mitered, for example, by a machine described as either a shaper or double end tenoner using a planer type cutting head. A final operation provides a longitudinal groove in the panel edge for receipt of a spline which serves to align and strengthen the bond when the adjacent panel edges are glued together.
The prior art shaping operation is executed by a planer device which includes a number of blades mounted generally parallel to the rotation axis of a blade mounting assembly. The blades engage the edge surface which is being formed upon movement of the panel and planer head. The particular Bimex structure identified above provides two sets of blades which are movable parallel to the axis of rotation so that different parts of these blades may be brought into contact with material being machined. This reduces the wear on the blades and lengthens their life.
While the apparatus referenced above has proven quite workable especially for composite material panels, the effective life for blades of such assemblies is limited. For example, blades in a standard cutter head have been found to be useful for trimming approximately 100 to 120 feet of panel. The blades must then be removed, reversed, resharpened or otherwise refurbished after such limited use. Generally, the need for replacement of the blades occurs because of the variable hardness of the different components in the composite panels. This causes different degrees of wear of the blade edge. Moreover, since during the cutting operation, the blade engages generally the same part of the panel of same thickness, hard portions of the panels cause higher blade wear. Blade life is limited by the action of the hardest or most abrasive portion of the panel being cut.
In an effort to overcome these limitations associated with the prior art, the present method and apparatus were devised.